We have recently reported that two EB virus-transformed human cell lines, on exposure to heat shock conditions, produce an antiviral activity. This activity has been characterized as interferon-Gamma (IFN-Gamma). One of the cell lines, GM3299, produces high levels of IFN-Alpha constitutively, whereas GM4408 produces very little (if any) IFN-Alpha. Initial characterization of the IFN-Alpha produced indicates the possibility that this is a species of interferon differing from PHA-stimulated T-lymphocyte IFN-Gamma. The very high levels of interferon activity induced in GM3299 by heat shock may reflect potentiation or synergism between IFN-Alpha and IFN-Gamma. We shall purify and characterize this 'novel' interferon. We shall characterize the induction process in detail and clone the IFN-Gamma gene. We shall attempt to define the nucleotide sequences involved in "heat-induction." Using cloned EB virus DNA segments, we shall examine the relationship, if any, between EB DNA synthesis and transcription and the interferon induction process. These experiments will be paralleled with in vivo studies on the effect of fever on interferon induction. We have measured the interferon levels in genital herpes-infected patients. High levels of IFN-Alpha are detected in the serum, and IFN-Beta in herpatic vesicles. PHA-stimulated lymphocytes produce 10-100 times more IFN-Gamma than stimulated lymphocytes of control individuals. Contrary to other reports, IFN-Gamma inhibits herpes plaque formation in culture. IFN-Alpha and IFN-Beta are less active. We shall examine the molecular basis of this antiviral activity of using cloned HSV genes. Recent reports indicate that murine IFN-Gamma is identical to macrophage-activating factor. This will be examined for human IFN-Gamma using monoclonal antibodies. We shall attempt to functionally separate the three functions of IFN-Gamma: antiviral, anti-proliferative, and macrophage activation.